Jay, you'll finds the relevant details on most of the manufacturers' websites. GT rods tend to get classed on a PE basis; for example, PE4-6, PE6-8, PE8-10 etc. Some rods are obviously able to fish a wider range and could cover say PE6-10. What you need to understand is that a PE6 rod from one manfacturer may not be the same as a PE6 rod from another manufacturer. Also, be careful of the PE classification itself. As an example, a Saltiga GT86 is designed for up to PE8 but as you would probably know, PE8 can range from 80lb line to 120lb in the case of the new Varivas GT SMT. That's a big difference.
I tend to look at GT rods as follows as a rough guide:
unde PE4 - light
PE4-6 - medium
PE6-8 - heavy
PE8-12 extra heavy
Selecting a rod is a combination of numerous factors. this would include:
size of fish you're targeting
terrain
reel you're proposing to use
line weight you want to fish
Budget
Physical ability
lures you intend to use
Duration of fishing etc
A number of the issues above are interdependent as well - they're not mutually exclusive.
Some rods are quite specialised as well. For example, a Carpenter SP-78-UHL is a rod that is made for big chuggers but is not ideal for suurface stickbaits.
Jay mentions the rolls royce of GT rods. Why these rods have the reputations they have may not be entirely apparent when you pick them up. After all, nearly all GT rods seem to be stiff and come armed with premium components (from the Ugly Stick Bluewater popping rods to the Fishermans). What you are assured of when you get a rod like a Fisherman, Carpenter, Smith etc are the thousand of hours of testing over the years. They are experts at building these rods and it is the subtle things that set them apart.
The best analogy I can draw is there is a reason why a Porsche or Ferrari handles so well. It is because these guys are experts at building these cars. This is their business and their speciality. The premium rods are like these cars in another sense. If you want one, you need to order it, wait and be patient!
